src/northbridge/via/vx900/early_smbus.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2011  Alexandru Gagniuc <mr.nuke.me@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <device/pci_ids.h>
#include "early_vx900.h"
#include <device/early_smbus.h>

#include <arch/io.h>
#include <console/console.h>

/**
 * \brief SMBUS IO ports in relation to the base IO port
 */
#define SMBHSTSTAT(base)		(u16)(u32)base + 0x0
#define SMBSLVSTAT(base)		(u16)(u32)base + 0x1
#define SMBHSTCTL(base)			(u16)(u32)base + 0x2
#define SMBHSTCMD(base)			(u16)(u32)base + 0x3
#define SMBXMITADD(base)		(u16)(u32)base + 0x4
#define SMBHSTDAT0(base)		(u16)(u32)base + 0x5
#define SMBHSTDAT1(base)		(u16)(u32)base + 0x6
#define SMBBLKDAT(base)			(u16)(u32)base + 0x7
#define SMBSLVCTL(base)			(u16)(u32)base + 0x8
#define SMBTRNSADD(base)		(u16)(u32)base + 0x9
#define SMBSLVDATA (base)		(u16)(u32)base + 0xa

static void smbus_delays(int delays)
{
	while (delays--)
		smbus_delay();
}

/**
 * Read a byte from the SMBus.
 *
 * @param dimm The address location of the DIMM on the SMBus.
 * @param offset The offset the data is located at.
 */
u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset)
{
	u8 val;

	/* Initialize SMBUS sequence */
	smbus_reset(smbus_dev);
	/* Clear host data port. */
	outb(0x00, SMBHSTDAT0(smbus_dev));

	smbus_wait_until_ready(smbus_dev);
	smbus_delays(50);

	/* Actual addr to reg format. */
	addr = (addr << 1);
	addr |= 1;		/* read command */
	outb(addr, SMBXMITADD(smbus_dev));
	outb(offset, SMBHSTCMD(smbus_dev));
	/* Start transaction, byte data read. */
	outb(0x48, SMBHSTCTL(smbus_dev));
	smbus_wait_until_ready(smbus_dev);

	val = inb(SMBHSTDAT0(smbus_dev));
	return val;
}

void enable_smbus(void)
{
	device_t dev;
	u8 reg8;
	u32 smbus_dev = (u32) SMBUS_IO_BASE;

	/* Locate the Power Management control */
	dev = pci_locate_device(PCI_ID(PCI_VENDOR_ID_VIA,
				       PCI_DEVICE_ID_VIA_VX900_LPC), 0);

	if (dev == PCI_DEV_INVALID) {
		die("Power Management Controller not found\n");
	}

	/*
	 * To use SMBus to manage devices on the system board, it is a must to
	 * enable SMBus function by setting
	 * PMU_RXD2[0] (SMBus Controller Enable) to 1.
	 * And set PMU_RXD0 and PMU_RXD1 (SMBus I/O Base) to an appropriate
	 * I/O port address, so that all registers in SMBus I/O port can be
	 * accessed.
	 */

	reg8 = pci_read_config8(dev, 0xd2);
	/* Enable SMBus controller */
	reg8 |= 1;
	/* Set SMBUS clock from 128k source */
	reg8 |= 1 << 2;
	pci_write_config8(dev, 0xd2, reg8);

	reg8 = pci_read_config8(dev, 0x94);
	/* SMBUS clock from divider of 14.318 MHz */
	reg8 &= ~(1 << 7);
	pci_write_config8(dev, 0x94, reg8);

	/* Set SMBus IO base */
	pci_write_config16(dev, 0xd0, SMBUS_IO_BASE);

	/*
	 * Initialize the SMBus sequence:
	 */
	/* Clear SMBus host status register */
	smbus_reset(smbus_dev);
	/* Clear SMBus host data 0 register */
	outb(0x00, SMBHSTDAT0(smbus_dev));

	/* Wait for SMBUS */
	smbus_wait_until_ready(smbus_dev);

}

static int spd_get_length(u8 spd_byte0)
{
	spd_byte0 &= 0xf;

	switch (spd_byte0) {
	case 0x3:
		return 256;
	case 0x2:
		return 176;
	case 0x1:
		return 128;
	default:
		break;
	}
	return 0;
}

void spd_read(u8 addr, spd_raw_data spd)
{
	u8 reg;
	int i, regs;
	u32 smbus_dev = SMBUS_IO_BASE;

	reg = smbus_read_byte(smbus_dev, addr, 2);
	if (reg != 0x0b) {
		printk(BIOS_DEBUG, "SMBUS device %x not a DDR3 module\n", addr);
		spd[2] = 0;
		return;
	}

	reg = smbus_read_byte(smbus_dev, addr, 0);
	if ((regs = spd_get_length(reg)) == 0) {
		printk(BIOS_INFO, "No DIMM present at %x\n", addr);
		spd[2] = 0;
		return;
	}

	for (i = 0; i < regs; i++)
		spd[i] = smbus_read_byte(smbus_dev, addr, i);
}

void dump_spd_data(spd_raw_data spd)
{
	int len, i;
	u8 reg;

	if ((len = spd_get_length(spd[0])) == 0) {
		printk(BIOS_DEBUG, "Invalid SPD\n");
		return;
	}

	/*
	 * I originally saw this way to present SPD data in code from VIA. I
	 * really liked the idea, so here it goes.
	 */
	print_debug("     00 01 02 03 04 05 06 07 07 09 0A 0B 0C 0D 0E 0F\n");
	print_debug("---+------------------------------------------------");
	for (i = 0; i < len; i++) {
		reg = spd[i];
		if ((i & 0x0f) == 0)
			printk(BIOS_DEBUG, "\n%.2x |", i);
		printk(BIOS_DEBUG, " %.2x", reg);
	}
	print_debug("\n");
}